膳食黄酮类化合物与牛血清蛋白的分子结构亲和力关系

用荧光滴定法研究了食用黄酮类化合物的分子结构及其与牛血清蛋白间的亲和力关系。研究证明食用黄酮类化合物与牛血清蛋白的结合过程在很大程度上受黄酮结构的影响,类黄酮中羟基的甲基化使其与牛血清蛋白的亲和力增长1～794倍。环A、B、C的羟基化作用对类黄酮与牛血清蛋白的亲和力也有很大影响,糖基化作用因共轭位置和糖种类的不同而使类黄酮与牛血清蛋白的结合力降低1～2个数量级。C2‖C3双键的加氢化作用使结合能力稍有减弱。与非聚合型儿茶酚和邻苯二酚型儿茶酚相比,聚合儿茶酚和邻苯三酚型儿茶酚与牛血清蛋白的亲和力更强。分配系数升高时,类黄酮与牛血清蛋白的亲和力增强;氢键的电子供体和受体数目增多时,类黄酮与牛血清蛋白的亲和力降低,表明疏水力是影响其相互结合作用的主要因素。

Molecular Structure-affinity Relationship of Dietary Flavonoids with Bovine Serum Albumin

The relationships between molecular structures of dietary flavonoids and their affinities for bovine serum albumin(BSA) were investigated by fluorescence titration analysis.The results indicated that the binding process with BSA was significantly affected by the molecular structures of flavonoids.The methylation of hydroxyl groups in flavonoids could enhance their binding affinities for BSA by 1 to 794 times.Hydroxylation on rings of A,B and C also strongly influenced the affinities for BSA.The glycosylation weakened the affinities for BSA by 1-2 orders of magnitude depending on the conjugation site and the class of sugar moiety.The hydrogenation of the C2‖C3 double bond slightly decreased the binding affinities.The galloylated catechins and pyrogallol-type catechins exhibited higher binding affinities for BSA than the non-galloylated catechins and catechol-type catechins,respectively.The affinities for BSA increased with the increase of partition coefficients and decreased with the increase of hydrogen bond donor and acceptor numbers of flavonoids,which suggested that the binding interaction was mainly caused by hydrophobic forces.